将 csv.DictReader object 类型数据转换为 non-iter 类型数据并按键合并值

Convert csv.DictReader object to non-iter type data and merge values by keys

在我的数据中:

myData='''pos\tidx1\tval1\tidx2\tval2
11\t4\tC\t6\tA
15\t4\tA\t6\tT
23\t4\tT\t6\tT
28\t4\tA\t3\tG
34\t4\tG\t3\tC
41\t4\tC\t4\tT
51\t4\tC\t4\tC'''

我用 header 作为键读取了这个数据,csv.DictReader。

import csv
import itertools

input_file = csv.DictReader(io.StringIO(myData), delimiter = '\t')
# which produces an iterator

''' Now, I want to group this dictionary by idx2, where
idx2 values is the main key and other have values merged into list that have same keys'''

# This groupby method give me
file_blocks = itertools.groupby(input_file, key=lambda x: x['idx2'])

# I can print this as
for index, blocks in file_blocks:
    print(index, list(blocks))

6 [{'val2': 'A', 'val1': 'C', 'idx1': '4', 'pos': '11', 'idx2': '6'}, {'val2': 'T', 'val1': 'A', 'idx1': '4', 'pos': '15', 'idx2': '6'}, {'val2': 'T', 'val1': 'T', 'idx1': '4', 'pos': '23', 'idx2': '6'}]
3 [{'val2': 'G', 'val1': 'A', 'idx1': '4', 'pos': '28', 'idx2': '3'}, {'val2': 'C', 'val1': 'G', 'idx1': '4', 'pos': '34', 'idx2': '3'}]
4 [{'val2': 'T', 'val1': 'C', 'idx1': '4', 'pos': '41', 'idx2': '4'}, {'val2': 'C', 'val1': 'C', 'idx1': '4', 'pos': '51', 'idx2': '4'}]

But, since the output is exhausted I can't print, use it more than once to debug it.

所以, 问题 #1:如何将其转换为非 iter-type 数据。

问题 #2:如何进一步处理此 groupby object 以将值合并到具有相同 group/blocks.

中的公共键的列表
Something like orderedDict, defaultDict where the order of the way the data is read is preserved:

{'6': defaultdict(<class 'list'>, {'pos': [11, 15, 23], 'idx1': [4, 4, 4], 'val1': ['C', 'A', 'T'], 'idx2': [6, 6, 6], 'val2': ['A', 'T', 'T']})}
{'3': .....
{'4': .....

我尝试的一些修复:

我宁愿在分组之前通过唯一键准备一个键:[值]:

update_dict = {}
for lines in input_file:
print(type(lines))
for k, v in lines:
    update_dict['idx2'] = lines[k,v]

我尝试的另一件事是确定我是否可以合并分组 object 中的数据: new_groupBy = {} 对于索引,file_blocks 中的块: 打印(索引,列表(块)) 对于块中的 x: 对于 k,v 在 x 中: 为 new_groupBy

做点什么

所以,对于你的第一个问题,你可以简单地具体化一个列表:

In [9]: raw_data='''pos\tidx1\tval1\tidx2\tval2
    ...: 11\t4\tC\t6\tA
    ...: 15\t4\tA\t6\tT
    ...: 23\t4\tT\t6\tT
    ...: 28\t4\tA\t3\tG
    ...: 34\t4\tG\t3\tC
    ...: 41\t4\tC\t4\tT
    ...: 51\t4\tC\t4\tC'''

In [10]: data_stream = csv.DictReader(io.StringIO(raw_data), delimiter="\t")

In [11]: grouped = itertools.groupby(data_stream, key=lambda x:x['idx2'])

In [12]: data = [(k,list(g)) for k,g in grouped] # order is important, so use a list

In [13]: data
Out[13]:
[('6',
  [{'idx1': '4', 'idx2': '6', 'pos': '11', 'val1': 'C', 'val2': 'A'},
   {'idx1': '4', 'idx2': '6', 'pos': '15', 'val1': 'A', 'val2': 'T'},
   {'idx1': '4', 'idx2': '6', 'pos': '23', 'val1': 'T', 'val2': 'T'}]),
 ('3',
  [{'idx1': '4', 'idx2': '3', 'pos': '28', 'val1': 'A', 'val2': 'G'},
   {'idx1': '4', 'idx2': '3', 'pos': '34', 'val1': 'G', 'val2': 'C'}]),
 ('4',
  [{'idx1': '4', 'idx2': '4', 'pos': '41', 'val1': 'C', 'val2': 'T'},
   {'idx1': '4', 'idx2': '4', 'pos': '51', 'val1': 'C', 'val2': 'C'}])]

至于你的第二个问题,试试这样的:

In [15]: import collections

In [16]: def accumulate(data):
    ...:     acc = collections.OrderedDict()
    ...:     for d in data:
    ...:         for k,v in d.items():
    ...:             acc.setdefault(k,[]).append(v)
    ...:     return acc
    ...:

In [17]: grouped_data = {k:accumulate(d) for k,d in data}

In [18]: grouped_data
Out[18]:
{'3': OrderedDict([('pos', ['28', '34']),
              ('idx2', ['3', '3']),
              ('val2', ['G', 'C']),
              ('val1', ['A', 'G']),
              ('idx1', ['4', '4'])]),
 '4': OrderedDict([('pos', ['41', '51']),
              ('idx2', ['4', '4']),
              ('val2', ['T', 'C']),
              ('val1', ['C', 'C']),
              ('idx1', ['4', '4'])]),
 '6': OrderedDict([('pos', ['11', '15', '23']),
              ('idx2', ['6', '6', '6']),
              ('val2', ['A', 'T', 'T']),
              ('val1', ['C', 'A', 'T']),
              ('idx1', ['4', '4', '4'])])}

注意,我使用了列表(和字典)理解。他们的工作方式相似。列表理解等同于:

data = []
for k, g in grouped:
    data.append((k, list(g))

虽然我使用的是 OrderedDict,但为了更好的衡量,这里相当于字典理解,因为在任何情况下,顺序似乎都很重要:

In [20]: grouped_data = collections.OrderedDict()

In [21]: for k, d in data:
    ...:     grouped_data[k] = accumulate(d)
    ...:

In [22]: grouped_data
Out[22]:
OrderedDict([('6',
              OrderedDict([('val2', ['A', 'T', 'T']),
                           ('val1', ['C', 'A', 'T']),
                           ('pos', ['11', '15', '23']),
                           ('idx2', ['6', '6', '6']),
                           ('idx1', ['4', '4', '4'])])),
             ('3',
              OrderedDict([('val2', ['G', 'C']),
                           ('val1', ['A', 'G']),
                           ('pos', ['28', '34']),
                           ('idx2', ['3', '3']),
                           ('idx1', ['4', '4'])])),
             ('4',
              OrderedDict([('val2', ['T', 'C']),
                           ('val1', ['C', 'C']),
                           ('pos', ['41', '51']),
                           ('idx2', ['4', '4']),
                           ('idx1', ['4', '4'])]))])

注意,我们可以一次完成所有操作,避免创建不必要的数据结构:

import itertools, io, csv, collections

data_stream = csv.DictReader(io.StringIO(raw_data), delimiter="\t")
grouped = itertools.groupby(data_stream, key=lambda x:x['idx2'])

def accumulate(data):
    acc = collections.OrderedDict()
    for d in data:
        for k,v in d.items():
            acc.setdefault(k,[]).append(v)
    return acc

grouped_data = collections.OrderedDict()
for k, g in grouped:
    grouped_data[k] = accumulate(g)

给定

import io
import csv
import itertools as it
import collections as ct    

data="""pos\tidx1\tval1\tidx2\tval2
11\t4\tC\t6\tA
15\t4\tA\t6\tT
23\t4\tT\t6\tT
28\t4\tA\t3\tG
34\t4\tG\t3\tC
41\t4\tC\t4\tT
51\t4\tC\t4\tC"""

第一部分

how to I convert it into non iter-type data

代码

以下是从迭代器中保留数据的方法 - 只需将其转换为列表即可:

>>> input_file = list(csv.DictReader(io.StringIO(data), delimiter = "\t"))
>>> input_file
[{'idx1': '4', 'idx2': '6', 'pos': '11', 'val1': 'C', 'val2': 'A'},
 {'idx1': '4', 'idx2': '6', 'pos': '15', 'val1': 'A', 'val2': 'T'},
 {'idx1': '4', 'idx2': '6', 'pos': '23', 'val1': 'T', 'val2': 'T'},
 {'idx1': '4', 'idx2': '3', 'pos': '28', 'val1': 'A', 'val2': 'G'},
 {'idx1': '4', 'idx2': '3', 'pos': '34', 'val1': 'G', 'val2': 'C'},
 {'idx1': '4', 'idx2': '4', 'pos': '41', 'val1': 'C', 'val2': 'T'},
 {'idx1': '4', 'idx2': '4', 'pos': '51', 'val1': 'C', 'val2': 'C'}]

或者使用列表理解:

>>> file_blocks = [(k, list(g)) for k, g in it.groupby(input_file, key=lambda x: x["idx2"])]
>>> file_blocks
[('6',
  [{'idx1': '4', 'idx2': '6', 'pos': '11', 'val1': 'C', 'val2': 'A'},
   {'idx1': '4', 'idx2': '6', 'pos': '15', 'val1': 'A', 'val2': 'T'},
   {'idx1': '4', 'idx2': '6', 'pos': '23', 'val1': 'T', 'val2': 'T'}]),
 ('3',
  [{'idx1': '4', 'idx2': '3', 'pos': '28', 'val1': 'A', 'val2': 'G'},
   {'idx1': '4', 'idx2': '3', 'pos': '34', 'val1': 'G', 'val2': 'C'}]),
 ('4',
  [{'idx1': '4', 'idx2': '4', 'pos': '41', 'val1': 'C', 'val2': 'T'},
   {'idx1': '4', 'idx2': '4', 'pos': '51', 'val1': 'C', 'val2': 'C'}])]

现在您可以重复使用 input_filefile_blocks 的数据。


第二部分

how can I process this groupby object further to merge the values to a list that have common keys within same group/blocks...

Something like orderedDict, defaultDict where the order of the way the data is read is preserved

def collate_data(data):
    """Yield an OrderedDict of merged dictionaries from `data`."""
    for idx, item in data:
        results = ct.OrderedDict()
        dd = ct.defaultdict(list)
        for dict_ in item:
            for k, v in dict_.items():
                dd[k].append(v)
        results[idx] = dd
        yield results
    

list(collate_data(file_blocks))

输出

[OrderedDict([('6',
               defaultdict(list,
                           {'idx1': ['4', '4', '4'],
                            'idx2': ['6', '6', '6'],
                            'pos': ['11', '15', '23'],
                            'val1': ['C', 'A', 'T'],
                            'val2': ['A', 'T', 'T']}))]),
 OrderedDict([('3',
               defaultdict(list,
                           {'idx1': ['4', '4'],
                            'idx2': ['3', '3'],
                            'pos': ['28', '34'],
                            'val1': ['A', 'G'],
                            'val2': ['G', 'C']}))]),
 OrderedDict([('4',
               defaultdict(list,
                           {'idx1': ['4', '4'],
                            'idx2': ['4', '4'],
                            'pos': ['41', '51'],
                            'val1': ['C', 'C'],
                            'val2': ['T', 'C']}))])]

itertools.groupby() 个元素的顺序由 collections.OrderedDict() 维护。 collections.defaultdict() 对象中的列表保留文件各行值的顺序(参见 input_file 中的字典)。